Parts of the aircraft and passenger belongings were discovered near the coastal city of Alexandria, the Egyptian military said in a statement.

"The searching, sweeping and the retrieval process is underway," military spokesman Brig. Gen. Mohammad Samir said.

The plane was carrying 56 passengers and 10 crew members when it left Paris' Charles de Gaulle Airport for Cairo late Wednesday night.

It disappeared from radar early Thursday as it flew to Cairo -- what should have been about a 3 1/2-hour flight.

The military said the wreckage was 180 miles north of the coastal city of Alexandria.

Debris confusion

A day earlier, the airline's vice chairman said wreckage of the plane had been found at sea, but those reports turned out to be false.

When searchers got close to the debris, they realized it was not from the missing airliner, Ahmed Adel said Thursday.

Hours after Adel retracted his statement Thursday, the military announced the sighting of the wreckage Friday.

"The presidency, with utmost sadness and regret, mourns the victims on aboard the EgyptAir flight who were killed after the plane crashed in the Mediterranean," the Egyptian presidency said in a statement.

The airline also expressed its condolences.

"EgyptAir sincerely conveys its deepest sorrow to the families and friends of the passengers onboard Flight MS804," it tweeted.

What went wrong?

While no theory has been completely ruled out, speculation on what caused the flight to crash centered on the possibility of a terror attack.

At some point before dropping off radar, the plane swerved 90 degrees to the left and then made a 360-degree turn to the right before plunging first to 15,000 feet, then 10,000 feet, Greek officials said.

"It's very difficult to come up with a scenario that jibes with some sort of catastrophic failure. (The evidence so far) leads us down the road to a deliberate act," said Miles O'Brien, an aviation analyst.

"But if you analyze this situation properly, the possibility of having a different action aboard, of having a terror attack, is higher than having a technical problem," said Sharif Fathi, the nation's aviation minister.

French officials urged caution, saying it's still too early to draw conclusions.

"All assumptions are reviewed but none is favored," Foreign Minister Jean-Marc Ayrault told France 2 network Friday. "We have absolutely no indication on the causes of this event."

Ayrault said his Egyptian counterpart Sameh Shoukry was not leaning toward terrorism as the cause of the crash.

"He said he wanted all possibilities to be examined," he told France 2.

Ayrault defended security measures at the Paris airport, saying they have been intensified since the November terror attacks.

Controllers tried to reach pilot

Shortly before the aircraft was scheduled to exit Greek airspace early Thursday, controllers tried to reach the pilots to transfer control to Cairo authorities. Despite repeated attempts, they received no response, Greece's Aviation Authority said.

Radar soon lost the plane's signal, just after it entered Egyptian airspace, the authority said.

The Airbus A320 "swerved and then plunged" before descending into the Mediterranean, Greek Defense Minister Panos Kammenos said.

Passengers and crew

Most of the passengers are Egyptian -- 30 in all. But also aboard are 15 French citizens, including an infant. There were also passengers from Iraq, Britain, Belgium, Kuwait, Saudi Arabia, Sudan, Chad, Portugal, Canada and Algeria, according to the Egyptian aviation minister.

Canada said two of its citizens were on the plane.

Australian Foreign Minister Julie Bishop said the British passenger had Australian citizenship as well. It is unclear whether any other passengers were dual citizens.

The search

Greece, France, the United States and other nations were searching about 130 nautical miles southeast of Karpathos, Greek aviation officials said.

The pilots have been identified as Mohamed Said Shoukair, who was the plane's captain, and first officer Mohamed Mamdouh Ahmed Assem, according to an official close to the investigation and a security source.

The head flight attendant was identified as Mirvat Zaharia Zaki Mohamed.

The plane's captain had about 6,000 flying hours, Adel said. Maintenance checks on the plane had reported "no snags."

Checks of the passenger manifest have so far resulted in no hits on terror watch lists, officials with knowledge of the investigation said.

An initial theory is that the plane was downed by a bomb, two U.S. officials said. Officials said the theory could change, with one senior administration official cautioning it is not yet supported by a "smoking gun."

The jet had routine maintenance checks in Cairo before it left for Paris, the airline said. Earlier Wednesday, the jet was also in Eritrea and Tunisia, data from flight tracking websites show.

The plane has been part of EgyptAir's fleet since November 2003, according to Adel.